Enzymic catalysis of glucuronyl transfer.

Group transfer reactions catalyzed by enzymes have assumed a position of intense interest in contemporary enzymology (1). Well known examples of radicals capable of being transferred in such reactions are methyl, glycosyl, aeetyl, phosphoryl, pept,idyl, nucleosidyl, and nucleotidyl, in addition to the transport of hydrogen as seen with the familiar nuoleot.ide coenzymes. In this paper we wish to report experimental evidence which establishes t,he phenomenon of an efficient enzyme-catalyzed transfer of the glucuronyl radical from a variety of donor substrates to a number of acceptor alcohols. This is accomplished by a soluble, stable, highly purified cell-free enzyme from liver which is in many respects indistinguishable from @-glucuronidase. These data supplement and extend the observations first reported in 1956 (2).